Which self-tapping screw for the dowel 6. How to choose the right drill for the dowel for fastening various objects

A screw is a fastener familiar to many, which consists of a rod with an external thread and a head with a recess called a slot. When screwing into the hole of the product, part or object, the screws form an internal thread in it. This is the main factor by which fasteners such as screw, screw, self-tapping screw, differences between which we will analyze below.

Countersunk screw

There are differences in the method of preparing a place for screwing in a screw based on the type of material of the product or object.

If the material has a soft texture (wood or plastic), then it does not need to pre-drill a hole for the screw. But there are times when a hole needs to be made. Then when drilling, remember that the diameter of this hole should be 70% of the diameter of the screw shaft. This "margin" must be left to compensate for the width of the channel when screwing into soft material. With solids, the situation is different. Here, screwing a screw cannot do without pre-drilling a hole deep into the dowel rod, and maybe even more.
Compared to screws or bolts, screws do not require an equivalent match between prepared hole diameter and shank size. Screws can be re-tightened up to a hundred times, which a fastener like a screw cannot boast of.

Screws can have heads in the form of squares, hexagons, semicircles, they are also secret and semi-hidden. Screws are also different in the type of slots, which are straight, cross-shaped and Torx-type

Types of screw heads

• secret
• semi-hidden
• semicircular
• Hexagonal
• Square

a - hidden, b - semi-hidden, c - round, d - hexagonal

It can also vary in slot (a slot is a recess in the head of a fastener):

• Straight
• cruciform

Differences between a screw and a self-tapping screw, or a self-tapping screw

Many craftsmen use screw and self-tapping screw, difference between which is not taken into account. Meanwhile, in vain. There are quite a few differences between them.

The thread and the smooth part are the components of the screw shaft. Diametrically, these parts are equal, so the material or product where the screw is screwed must be soft. So the smooth part will go in without problems. What is the difference between self-tapping screws in this case? They consist of a fully threaded part or a smooth and threaded part. In the latter case, the circumference of the smooth part of the self-tapping screw is smaller than the diameter of the thread. The self-tapping screw is sharper, and the screw, on the contrary, has a “blunt” end. The thread characteristics of these fasteners are also different: the height and pitch of the screw thread is less than that of the self-tapping screw. The material of manufacture of these fasteners is selected in accordance with their application. Hard steel grades are the material for the manufacture of self-tapping screws, and soft steel grades are used for screws, since they are designed for screwing.

Screws require the preparation of recesses for screwing them. What is it for? All The end of the screw is not pointed, so the hole will allow you to create a guide recess for it. In this case, the hole must be clean. Then, when screwing in, there will be no problems, especially when entering the hole of the smooth part.

For self-tapping screws, there is no need to prepare a preliminary hole. These fasteners have a pointed end, and a smooth thread will allow you to almost effortlessly screw the self-tapping screw into the material in a given direction.

Most often, self-tapping screws are fully threaded with a large thread pitch. This allows less material to be displaced and minimizes the chance of cracking in the material. But fully threaded screws also have disadvantages. This is especially true for strength characteristics. For example, if we compare screws and self-tapping screws of the same size and material of manufacture, then the screw will have the best fastening strength. Although self-tapping screws are made from harder steel alloys.

Dowel

It is not always possible to fix something with a single screw or self-tapping screw. Sometimes an auxiliary part is also required - a dowel, which makes it possible to well fix these products in the required material. Dowels consist of 2 parts: non-expansive and spacer parts. Sometimes a cuff is included with the dowel, which does not allow it to fall into the recess.

The fastening of the dowel in the prepared hole occurs either due to those parts tightly pressed into the hole, or due to the different diameters of the back and front parts. There are 2 ways to place a dowel in a hole: screwing in and driving in, depending on the design features.

Two white dowels - for solid materials, two blue - with an enlarged spacer for hollow and porous materials

Depending on the design of the dowel, it is either hammered into the hole or twisted.

Universal dowel suitable for sheet materials. Washers put on the dowel imitate the material to be fixed

If you don't know how to choose a dowel for a self-tapping screw or how to choose a screw for a dowel, then the table below will help you with this. The depth of the hole prepared for the screw or self-tapping screw must be greater than the fastener itself. Such a gap is left for particles of dust or material in which holes are drilled. To engage the entire spacer part of the dowel, the screw must extend slightly beyond its limits.

Table for the selection of a dowel for a screw, the size of the hole for the selected dowel
Dowel		dowel hole		screw diameter, mm
diameter, mm	length, mm	drill diameter, mm	drilling depth, mm
5	25	5	30	3,5 - 4,0
6	30	6	36	4,0 - 5,0
6	40	6	46	4,0 - 5,0
6	50	6	56	4,0 - 5,0
8	40	8	48	4,5 - 6,0
8	50	8	58	4,5 - 6,0
8	65	8	73	4,5 - 6,0
10	50	10	60	6,0 - 8,0
10	80	10	90	6,0 - 8,0
12	60	12	72	8,0 - 10,0
14	70	14	84	8,0 - 10,0

Dowel selection table for self-tapping screw, hole size for the selected dowel
self-tapping screw		Dowel		dowel hole
Diameter, mm	Length, mm	Diameter, mm	Length, mm	Drill diameter, mm	Drilling depth, mm
3	12, 16, 20, 25, 30, 35, 40	5	12, 16, 20, 25, 30, 35, 40	5	16, 20, 25, 30, 35, 40, 45
3,5		6	12, 16, 20, 25, 30, 35, 40, 45, 50	6	16, 20, 25, 30, 35, 40, 45, 50, 55
4		5 or 6	12, 16, 20, 25, 30, 35, 40, 45, 50, 60, 70	5 or 6	16, 20, 25, 30, 35, 40, 45, 50, 55, 65, 75
4,5		6 or 8	16, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80	6 or 8	20, 25, 30, 35, 40, 45, 50, 55, 65, 75, 85
5	20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100	6 or 8	16, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100	6 or 8	20, 25, 30, 35, 40, 45, 50, 55, 65, 75, 85, 95, 105
6		8 or 10	40, 45, 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, 200	8 or 10
8	40, 45, 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, 200	10 or 12 or 14	40, 45, 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, 200	10 or 12 or 14	45, 50, 55, 65, 75, 85, 95, 105, 130, 150, 170, 190, 220
10		12 or 14	40, 45, 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, 200, 220, 240, 260	12 or 14	45, 50, 55, 65, 75, 85, 95, 105, 130, 150, 170, 190, 220, 230, 260, 280

Knowledge of how to choose a drill for a dowel is relevant in situations where it is necessary to drill a hole to fix this fastener in it. Dowels are used in cases where it is necessary to fix various objects on the wall surface - furniture elements, photographs, paintings, etc. The reliability of fastening will largely depend on how correctly the drill is selected to obtain a hole in which the dowel will be placed.

What to consider when choosing a drill for a dowel

Select a drill to create a hole in which the dowel will be fixed, taking into account:

• the material from which the wall itself is made, as well as its finishes;
• estimated loads of the fastener.

The drill should also be selected depending on the diameter of the fasteners used. On the outer surface of factory-made dowels, as a rule, there is a marking that allows you to correctly select drills of the appropriate diameter for them.

Table 1. Selection of a drill and a self-tapping screw for a dowel

It is important to know not only how to choose a drill for a dowel, but also how to drill a hole correctly. If it is necessary to drill a hole in the wall for a dowel with a diameter of 10 mm, then first use a drill with a diameter of 8 mm and an impact drilling mode. After the hole is drilled, the tool is replaced with a drill with a diameter of 10 mm and they work without using the shock drilling mode. This approach will allow you to get a hole of the required diameter in the wall with even and neat edges.

If you need to drill a concrete wall, it is better to use a Pobedite drill, which will cope with such a durable material without any problems. The selected cutting tool must be at least 3 mm longer than the dowel itself. If this requirement is neglected, the dowel will not fully enter the resulting hole, in the final part of which, as a rule, dust and pieces of crumbled material accumulate. In addition, the shape of the bottom of the hole may not match the shape of the tip of the fastener.

How to fasten objects with a small weight

In order to fasten objects that are light in weight, use a quick mounting dowel. It is commonly used to fasten light objects to building structures made of brick and reinforced concrete.

As a rule, to solve this problem, a dowel is selected, the diameter of which, like the transverse size of the drill, is 6 mm. In this case, the length of the fastening element depends on the thickness of the wall of the object fixed with its help. If it is necessary to select a dowel for mounting on a wall, then its length should be at least 4 cm, but if mounting is performed on the ceiling, fasteners of at least 6 cm in length are needed.

Fixing Medium Weight Items

Fixing objects that differ in average weight is carried out using impact dowels. In this case, the transverse dimensions of the dowels, as well as the corresponding drills, must be at least 8 mm. The dowel selected for this purpose must go into the wall to a depth of at least 6 cm, and when attached to the ceiling surface - to a depth of 8 cm. To securely fix an object of average weight (up to 10 kg) on ​​a wall or ceiling, you must use 4 dowels at the same time.

Installation of items with significant weight

For fixing heavy objects (furniture cabinets, shelves, TV stands, etc.), you need to choose a dowel, also of the shock type. In this case, the diameter of such a dowel, as well as the transverse size of the drill, must be at least 10 mm. Such dowels are deepened into the walls by 6 cm, and into the ceiling by 8 cm. For reliable fastening of heavy objects, as a rule, at least 6 dowels are used.

Anchor bolts are used to fasten the horizontal bar and stairs, the diameter of which must be at least 8 mm. Such bolts are deepened into the surface of the walls by 6 cm, and into the ceiling by 8 cm.

Types of anchor bolts

Anchor bolts used to fasten various objects are divided into three main types:

1. anchor bolts with a nut, which, after mounting the fastener, is tightened with a cap or open-end wrench (with the help of such bolts, hidden type fasteners are made);
2. anchor bolts with a self-locking nut, which is tightened with a Phillips screwdriver (such bolts can be used to fasten in places that are visible);
3. double-spaced anchor bolts are the most reliable fasteners that are used to fix even very heavy objects.

How to mount on unreliable surfaces

Very often there is a need to fasten objects on unreliable surfaces, which include plasterboard walls, building structures in old brick houses, etc. When performing fastening on such surfaces, the following recommendations should be followed.

• Dowel elements are best chosen from nylon, while their diameter should be 10-12 mm. The diameter of the pobedit drill, with which the hole for fasteners will be made, must be 2 mm smaller than the transverse dimension of the selected dowel.
• Drilling must be performed in one step, without changing the drill, while the impact mode should not be used so as not to destroy the walls of the hole being formed.

A dowel-screw is a fastener used to fix various products in a solid base. The principle of operation is based on the friction force that occurs when a screw is screwed into the dowel.

Brief historical background

The name of the dowel's inventor and the date of its invention are unknown. But January 14, 1913 is the day the Englishman John Joseph Rawlings received a patent for this fastener.

The first devices of this kind were made of wood. Today, polyethylene, polypropylene and metal dowels are produced.

In addition, the use of nylon dowels is widespread - their use allows you to solve many problems. These fasteners complete with screws are appropriate to use when working with any material.

Description

Nowadays, no repair work can be imagined without the use of dowels. You always need to attach something to a wall or ceiling surface. Only if the walls and ceiling are made of wood, you can use nails and a hammer. In all other situations, dowel fasteners are indispensable.

There is a wide range of similar products on sale, differing from each other in the material of manufacture and the method of retention. In addition, the weight and size of the dowel-screws can be very different.

The mounting dowel can be not only polypropylene, but also nylon. The use of the former is possible only in interior decoration, since sub-zero temperatures contribute to the formation of cracks on them. And nylon fasteners are equally well suited for both indoor and outdoor use.

The expansion dowel is used when fastening structures to hollow blocks, concrete and brick. Fixation occurs with the help of special antennae. They securely hold the dowel and prevent it from turning. There are separate types of dowels designed for a construction gun. Despite the different installation method, they are quite effective.

The specifics of the dowel-screw

As you can see in the photo of the dowel-screw, it can be either with or without a locking collar. The dowel with a shoulder is usually made of nylon. It is used in outdoor installation work. The stoppers hold fasteners, preventing them from falling into the hole.

The fastener without collar is made of polyamide. Its distinguishing features are a through hole, longitudinal ribs and a non-expansive top. Such a design solution greatly simplifies screwing in, increasing the degree of expansion of the dowel.

And the fixed top protects the plastered surface from cracks. In addition, collarless fasteners are resistant to atmospheric precipitation and their service life is much longer.

- This is a specialized fastener used for mounting and fixing various structures to the walls of buildings. The most popular are dish type products.

The dowel-screw for drywall can be either plastic or metal. Its purpose is to fix products on plasterboard or gypsum-fiber sheets and porous concrete.

Metal fasteners do not require pre-drilling holes - they have a feather drill at the end, and the spacers are threaded. Installation of such a dowel occurs with a screwdriver.

The principle of operation of a universal dowel-screw in a thick wall is similar to the principle of operation of a conventional spacer. If the wall is thin, then after passing it, the dowel is screwed onto the screw and tied into a knot, which makes the fastener as reliable as possible.

The scope of the mounting dowel-nail is the quick installation of a double-glazed window, plinth, lathing, etc. The component is a nail that has a knurled thread with a reverse cone for better fixation. For its installation and a screwdriver and a hammer.

The purpose of the adjusting dowel is to fix wood products during the internal arrangement of buildings. It allows you to do without the use of pads and wedges for leveling an uneven wall surface.

For the installation of household appliances, it is permissible to use the fasteners supplied with it. They are calculated with the required margin of safety. When choosing dowel-screws on your own, you must take into account the mass of the load and the material of the wall.

To fix a chandelier or suspended ceiling system, opt for special dowels equipped with deep transverse notches and spacer ribs.

Photo dowel-screws

Dowel- an auxiliary element for fasteners, providing reliable adhesion of self-tapping screws or screws to the supporting base.

Dowels are made of plastic (polypropylene, polyethylene, nylon) and metal (iron, stainless steel, brass). The dowel can be conditionally divided into two parts. Spacer (in the photo below, the left side of the dowel), it is responsible for the force of holding the screw in the material, and non-expandable (in the photo below, the right side of the dowel). The non-expansion part of the dowel is needed in order not to destroy the soft layer of materials. For example, you install a dowel in a plastered brick wall, if there is no non-expandable part, then when you twist the self-tapping screw around the dowel, the plaster will collapse. You hang the wall cabinet by the base through the chipboard, then the length of the spacer should be equal to the thickness of the chipboard plus the size of the plaster layer, it turns out about 30 mm.

The non-expansion part of the dowel may have a countersunk, cylindrical or round flange. The flange does not allow the dowel to sink into the hole of the material to be fixed or into the wall. The use of dowels with a flange is convenient if the flange does not interfere.

When screwing the self-tapping screw, the expansion part of the dowel, which has an inner diameter much smaller than the diameter of the dowel, tries to move apart, but the wall material interferes and the plastic of the dowel is compacted under high pressure, connecting the self-tapping screw with the wall into one whole.

Dowels for fixing products on a plasterboard wall

For fixing objects on plasterboard walls, a special dowel is designed, the end of which is equipped with cutting edges that act as a drill. To install such a dowel in a plasterboard wall, it is not necessary to pre-drill a hole in it, which allows you to fix the object on the wall in the absence of a drill and a drill.

After installation, a self-tapping screw is screwed into the dowel without changing the geometry of the dowel. The dowel can be easily unscrewed from drywall and reused.

There is another special dowel for attaching products to a drywall wall called Molly (Molly). Its builders call it “Butterfly”, because when screwing in a self-tapping screw, the expansion part of the dowel diverges to the sides behind the inside of the drywall, taking the form of butterfly wings. This is due to the fact that at the end of the expansion part there is a thickening into which the self-tapping screw is screwed, folding the expansion part of the dowel in half, firmly fixing the dowel in the plasterboard.

Such a dowel allows you to fix a product weighing up to 10 kg on drywall. Here is an example of attaching a large mirror to a plasterboard wall using a Butterfly dowel.

Choosing a dowel for a self-tapping screw

After the choice of the type of self-tapping screw and dowel for wall mounting is made, it remains to choose, using the data given in the table below, the size of the self-tapping screw and the corresponding dowel. Decide on the diameter and depth of the hole for installing the dowel.

Due to the lack of an international standard for self-tapping screws and dowels, many manufacturers produce according to their own internal standards. Therefore, it is impossible to accurately indicate all dimensions, but in the vast majority of cases, the dimensions coincide with an accuracy sufficient for practical use.

Dowel selection table for the selected self-tapping screw, hole size for the selected dowel
self-tapping screw		Dowel		dowel hole
Diameter, mm	Length, mm	Diameter, mm	Length, mm	Drill diameter, mm	Drilling depth, mm
3	12, 16, 20, 25, 30, 35, 40	5	12, 16, 20, 25, 30, 35, 40	5	16, 20, 25, 30, 35, 40, 45
3,5		6	12, 16, 20, 25, 30, 35, 40, 45, 50	6	16, 20, 25, 30, 35, 40, 45, 50, 55
4		5 or 6	12, 16, 20, 25, 30, 35, 40, 45, 50, 60, 70	5 or 6	16, 20, 25, 30, 35, 40, 45, 50, 55, 65, 75
4,5		6 or 8	16, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80	6 or 8	20, 25, 30, 35, 40, 45, 50, 55, 65, 75, 85
5	20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100	6 or 8	16, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100	6 or 8	20, 25, 30, 35, 40, 45, 50, 55, 65, 75, 85, 95, 105
6		8 or 10	40, 45, 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, 200	8 or 10
8	40, 45, 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, 200	10 or 12 or 14	40, 45, 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, 200	10 or 12 or 14	45, 50, 55, 65, 75, 85, 95, 105, 130, 150, 170, 190, 220
10		12 or 14	40, 45, 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, 200, 220, 240, 260	12 or 14	45, 50, 55, 65, 75, 85, 95, 105, 130, 150, 170, 190, 220, 230, 260, 280

The table should be used as follows. Let's say you need to hang a bookshelf with a maximum possible weight of 100 kg with two hinges on a brick wall. Since the shelf will be suspended on two self-tapping screws, the load on one self-tapping screw will be 50 kg. Choose from the table, a self-tapping screw with a universal thread, with a hemispherical head, with a diameter of 6 mm, a length of at least 80 mm. The dowel is suitable standard, the simplest. From the table we see that there is such a standard size of a self-tapping screw; a dowel with a diameter of 8 or 10 mm and a length of 80 mm is suitable for it. Since there is a drill with a diameter of 8 mm, we also choose a dowel with a diameter of 8 mm. To install it, you need to drill a hole with a diameter of 8 mm to a depth of 85 mm.

Making a dowel from improvised material

As a dowel, you can successfully use a furniture dowel. It is made from solid wood. Diameter 8 mm, length 40 mm, with longitudinal ribs. Previously, in the manufacture of furniture, fastening with dowels was widespread.

Sometimes there is a need to urgently fix an object on the wall, but there is no ready-made factory-made dowel at hand. In this case, you can independently plan it out of any dry piece of wood. A leg from a chair or stool will do. This has always been done before, for the reason that there were no plastic dowels on sale. With a homemade dowel, it is advisable to chamfer on one side, so that it is easier to hammer into the wall.

In order to screw a self-tapping screw into a wooden dowel, it is necessary, after driving it into the wall, to drill a hole in its center with a diameter slightly less than the diameter of the threaded part of the self-tapping screw.

A good dowel can be made from a television cable, in which the central core is insulated from the braid with polypropylene, cutting off a piece of the required length from it. To do this, remove the outer insulation and shielding braid, remove the central core. Next, cut the cut piece of insulation in half to a third of its length. In the uncut part, drill a hole equal to the diameter of the self-tapping screw. On the outside of the dowel, it is desirable to make notches with a soldering iron so that the dowel does not rotate in the wall when the screw is screwed.

You get a dowel, no worse than an industrial design. True, there is a lot of fuss, but if you only need a few, then it makes sense to make it yourself.

Sometimes unexpected things happen when drilling a hole in a wall. The drill, due to the inhomogeneity of the wall material or if it fails to hit the joint of bricks, drills a hole not very accurately, and even much larger than a dowel. The dowel dangles, and in this case there will be no self-tapping screw to hold in the wall. Sometimes the wall is very loose and a large piece of it breaks off. But there is a simple solution that I have been using since time immemorial.

An aluminum or copper wire is wound onto the self-tapping screw, with a diameter equal to the thread pitch of the self-tapping screw or screw. It turns out a metal dowel with a thread. Since I came across a dowel with a double thread, I wound the wire in two passes. In such a wire dowel, the self-tapping screw is easily twisted and unscrewed. To prevent the wire dowel from turning in the wall, you should make edges on it with a file with a file.

The dowel is mounted in the wall as follows. A solution of cement, alabaster, gypsum or other similar mortar is diluted, a drilled hole is filled and a wire dowel is inserted with a self-tapping screw screwed into it until drowning in this solution. If it is hard to insert, you can tap with a hammer. After the mortar has hardened, the self-tapping screw can be unscrewed and the desired item can be hung on the wall. It will hold securely.

Sometimes it happens that a hole drilled in the wall with a drill of a given diameter does not provide a tight fit for the dowel, and when screwing the self-tapping screw into the dowel, it turns. In this case, you can use the composition "Liquid nails". From the tube, the drilled hole in the wall is completely filled with mortar and the dowel is immediately inserted into it. After half an hour, it will be possible to safely twist a self-tapping screw into the dowel. Will hold tight.

With the help of liquid nails, according to the technology described above, it is also possible to securely fix a standard plastic dowel in a wall lined with porous material, such as foam concrete.

There are times when the dowel cannot be completely driven into the hole, and it protrudes a little, but cannot be removed. The protruding part must be removed. It can be cut with a hacksaw blade for metal.

To exclude damage to the wall covering, it is enough to take a small sheet of sandpaper, make a hole in it with a diameter equal to the diameter of the dowel, put it on the dowel with the emery side to the wall and carefully cut it off. The wall covering will remain intact.

A dowel-screw is a fastener designed to secure any objects and structures in solid solid materials. The principle of operation is based on the friction that occurs when the dowel is expanded by a screw, screw, nail, etc. installed in it. Consider the main representatives of this attribute of the construction process.

Mounting dowel - from what and for what?

Who and when invented the dowel is unknown, but the first patent for the invention was received by John Joseph Rawlings on January 14, 1913 in London. Today, not a single repair is complete without the need to nail something to the ceiling or walls. And if in houses with wooden walls the problem is easily solved with a hammer and nails, then attaching something to concrete walls without a dowel will not work. There are a huge number of such devices, they differ in material and the principle of retention. There is also plenty to choose from for the length and weight of the dowel-nail.

Until recently, the dowel was more often cut from pieces of wood and inserted into a drilled hole in the wall. Now hardly anyone uses this archaic method - the industry produces a lot of dowels, for any materials and for all occasions. They are made of plastics (polyethylene, polypropylene) and metal. The most commonly used standard dowel is a nylon drive-in dowel - it allows you to solve almost all household problems. Such devices, in combination with self-tapping screws, can be used in any wall material.

The mounting dowel is made of both propylene and nylon. Polypropylene can only be used indoors, because. this material does not serve well at low temperatures - it cracks. Nylon products work well in all conditions. The spacer can be used when working with solid material (concrete, brick) and with hollow blocks. It is fixed with the help of special antennae that firmly hold it and do not allow it to turn in the hole.. Some types of fasteners are a dowel for a mounting gun, the principle of its fastening and appearance are somewhat different from the standard ones with manual installation, but the efficiency does not suffer from this, somewhere even this will be the most reliable option.

Dowel-screw - features of fastening to various surfaces

The construction expansion dowel with a locking shoulder is made of nylon. Such varieties are used mainly in the installation of building structures. Locking collars do not allow the dowel to fall into the hole; this device is used mainly for outdoor work. The product without shoulder is made of high quality polyamide. Such a dowel has a through hole, longitudinal ribs and a non-expansive upper part. Thanks to this design, the screwing of the self-tapping screw is simplified, the expansion of the dowel is increased, and the stationary upper part protects the plaster layer from cracking and shedding. This option is weather resistant and durable.

The dowel for is made of both plastics and metal. It is intended for fastening any elements to slabs of drywall, gypsum fiber or porous concrete. For metal products, it is not necessary to pre-drill a hole - their tip looks like a feather drill, and the spacer part looks like a coarse thread. This dowel is screwed into the body of drywall or porous concrete using a screwdriver.

Mounting dowel-nail is designed for quick fixing of windows, skirting boards, battens, etc. to any surface. It is sold in a set with a nail, which has a knurled to hold it. The knurling is made in the form of a thread with a reverse cone. Such a nail-screw can be screwed in with a screwdriver, or it can be hammered in. The reverse knurling cone securely fixes the part in the wall. It is rational to use such a device in mass production, because. the ability to hammer a screw significantly speeds up the work. Adjusting dowel is designed for mounting wooden structures for interior decoration. The split dowel allows you to level the unevenness of the load-bearing walls without the use of wedges and blocks.

The universal dowel in a thick wall works as a simple spacer, and in a thin wall, after passing through the wall and getting into the cavity, the product is wound on a screw and tied into a knot, as a result, a reliable fastening is obtained.

For fastening home appliances (air conditioner, extractor hood, etc.), you can safely use the fasteners supplied in the kit. They are always calculated with the necessary margin of safety. When choosing dowels yourself, you need to be guided by the material of the walls and the weight of the element to be fixed. For fastening, for example, a Swedish wall, the fastening depth must be at least 80 mm, and the wall material is concrete or brick, it is absolutely impossible to fasten heavy objects to plasterboard walls. For fixing chandeliers, false ceilings, etc. you need to choose special dowels with deep transverse notches and expansion ribs. In specialized stores, in case of difficulty, sales assistants can give qualified advice.

Construction dowel - special types of fasteners

The dowel "butterfly" is used in work with thin walls. The cut part passes through the wall and opens when the screw is tightened from the back side. To prevent the product from turning, a cuff is provided. The fastening is fixed and durable. Frame dowels are used for fixing door and window frames. Two types are produced - for solid solid walls and for hollow soft walls. The length of the dowel must be chosen in such a way that it passes through several jumpers, then the spacer part will provide a secure fit. Varieties are produced with a length of 60-360 mm.

A separate group consists of dowels, which are called facade connectors. They are designed to be attached to any surface. This is also a spacer product, which has an enlarged shoulder with a plate so that soft material (mineral wool, fiber boards) does not slip off the mount. Facade dowels are made of reinforced polyamide with increased impact strength.

Anchor dowels consist of two parts: a sleeve with slots (collets) and a rod. The rod is screwed into the sleeve, while bursting the collets and rigidly fixes the structure in a pre-drilled hole. They can be used for hard, durable material. Loose and porous collets can be destroyed under mechanical action, and the necessary rigidity of the connection will not be achieved. The protruding part of the rod can have both external and internal threads. Accordingly, fastening is carried out using a nut or screw (bolt). The thread is most often metric.

Chemical types of building dowels

Chemical dowels-anchors are divided into two groups: injection and ampoule. Injection anchors are more common. The role of the dowel is performed by the adhesive composition, which is squeezed out of the cartridges into the drilled hole. Cartridges are available in capacities up to 800 ml. Work is carried out using construction syringes, similar to those used to fill sealants. Fasteners can be very different - screws, screws, nails, anchors. The cost of such dowels is commensurate with the cost of conventional ones, but they significantly benefit in the speed of installation work. In addition, the composition fills all the voids, which is convenient when working with porous materials, because. this increases the strength of the connection.

An ampoule dowel is a hermetically sealed cylinder with an adhesive composition. The ampoule is placed in the prepared hole, then a metal anchor is screwed in or driven in with force. The ampoule collapses, the glue fills the space and hardens on contact with air. Synthetic resin is used as an adhesive. The resin may consist of two components, in which case the ampoule should be double. With the help of such a dowel, installation is very convenient and fast. The fastening is strong and quite rigid. The disadvantage is the high cost, it makes sense to use only in very responsible work.